The joke here is great, but what is really striking to me is how the artist, even with their simple drawing style, perfectly captured the affect of each person pictured. The clerk with a bit of anxiety delivering bad news yet with detached indifference, the other mechanic thinking "goddamit, another one of these. I don't get paid enough...", and the patron just ~~exacerbated~~ exasperated by the whole thing and having to once again make a bad choice from a menu of worse choices.
I always thought it took much more artistic talent/effort to communicate these feelings, but this comic is an eye opener for me for how simple it is drawn, but how effective in communicating.